Originally the 連用形(ren'yōkei, “stem or continuative form”) of verb 鋏む(hasamu, “to be tightly between two things, to be inserted in between””),[1][2] itself apparently deriving from hasa (“narrowness between other things”, likely cognate with 細hoso, “skinny, narrowness within the thing itself”) + auxiliary suffix む(mu, “to be or become like something”).

Cognate and homophonic with 挟, 挿 (​hasami): “being stuck in between other things”.

Probably originally an abbreviation of synonym yattokobasami,[1] with the yattoko portion possibly an alteration of 焼き床(yakidoko, “the cooking bed of an oven, or the firing bed of a kiln”, possibly formerly read as yakitoko, literally “burning or cooking bed”), perhaps used as a dialect word referring to the forge; compare 火床(hidoko, “hearth; a firepit, such as beneath a boiler”, literally “fire bed”).